Betty Ross disappeared without a trace two years ago.
My first theory about what happened that day is that she was murdered by a thief who was trying to rob in her house. He was discovered and lost his nerves being unable to rob anything, murdering her and hidding the body to avoid clues.
My second theory is similar except from the murder wasn't a thief, but her husband. His first idea was asking for a ransom, but at the end, he realized that it could be dangerous and changed his mind.
The last one is the most unbeliveable: Betty Ross was kidnapped by aliens. Why not?